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SCIENCE TECH: Jurnal Ilmiah Ilmu Pengetahuan dan Teknologi
Published by Universitas Sarjanawiyata Tamansiswa
ISSN : 24606286     EISSN : 25793624     DOI : 10.30738/science tech.v2i1.396
Core Subject : Science, Agriculture, Engineering,
Agriculture, Biological Sciences & Forestry Chemistry Computer Science & IT Engineering Materials Science & Nanotechnology
Jurnal SCIENCE TECH adalah jurnal yang diterbitkan oleh Lembaga Penelitian dan Pengabdian kepada Masyarakat (LP2M) Universitas Sarjanawiyata Tamansiswa (UST) Yogyakarta. Jurnal ini diharapkan sebagai media bagi dosen, peneliti, praktisi, mahasiswa dan masyarakat luas yang memiliki perhatian terhadap bidang dan perkembangan ilnu pengetahuan dan teknologi. Jurnal SCIENCE TECH terbit dua kali setahun yaitu Januari dan Agustus, setiap terbit 8 artikel.
Arjuna Subject : Umum - Umum
Articles 141 Documents
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Humanitarian Logistics Optimization for Flood Preparedness: An Integrated Model for Post-Aids Allocation Trihardani, Luki; Sabilarrozak, Billy Maulana; Erdiansyah, Sandra Ravi
Science Tech: Jurnal Ilmu Pengetahuan dan Teknologi Vol 11 No 2 (2025): August
Publisher : Universitas Sarjanawiyata Tamansiswa

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.30738/st.vol11.no2.a19282

Abstract

Flooding continues to pose a major challenge in urban areas of developing countries, necessitating effective humanitarian logistics, particularly during the preparedness phase. However, the absence of an optimized aid post-placement strategy remains a significant barrier to efficient aid distribution. This study presents a humanitarian logistics preparedness model that integrates K-means clustering with the Set Covering Location Problem (SCLP) to enhance aid post allocation. The clustering technique categorizes affected areas based on geographical proximity and flood severity, ensuring a more effective resource distribution. Compared to traditional district-based grouping, the proposed approach improves resource allocation efficiency by 5.61%. The model was tested using Excel Solver under varying disaster impact scenarios. Findings indicate that in the 100% affected scenario, 37 villages were covered by 18 aid posts, with round-trip distance of 74.72 km. In the 50% affected scenario, 19 villages were served by 8 aid posts, with the distance reduced to 33.65 km. The results highlight the importance of integrating clustering techniques with optimization models to improve data-driven humanitarian logistics planning. The proposed framework facilitates systematic aid distribution, making it a scalable solution that can be adapted to other disaster-prone regions to strengthen flood disaster response strategies
2D Modelling of the Breakdown Voltage of Hybrid Dielectric (Gas and Solid) System Muzamil, Sanupal; Wisnujati, Andika
Science Tech: Jurnal Ilmu Pengetahuan dan Teknologi Vol 11 No 2 (2025): August
Publisher : Universitas Sarjanawiyata Tamansiswa

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.30738/st.vol11.no2.a19380

Abstract

Sulfur hexafluoride (SF6) has been used over decades due to its excellent dielectric, arc quenching and heat transfer properties, but has tremendous global warming potential. It is therefore mandatory to find more environmentally friendly alternatives by designing of future eco-friendly hybrid insulation (solid and gas) system that require a thorough understanding of the evolution of electric field in such structure. A numerical model was developed using finite element method (FEM) of a commercial software Comsol® Multiphysics. Using electrostatic equations, the 2D model stability, 2D boundary model and  voltages are varied in order to identify their influence on the electric field distribution. Numerical simulations show that maximum electric fields will vary significantly according to distances of point-dielectric (gap). The maximum electric field increases if the gap (electrode tip-planar) size is shorter. Additionally, the electric field is not linearly spread in solid dielectric material and more concentrated around the edges of solid dielectric.
Sentiment Analysis untuk Mengidentifikasi Faktor Penunjang Kesuksesan Feeder Wira Wiri Suroboyo Bellanov, Agrienta; Irawati, Desrina Yusi
Science Tech: Jurnal Ilmu Pengetahuan dan Teknologi Vol 11 No 2 (2025): August
Publisher : Universitas Sarjanawiyata Tamansiswa

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.30738/st.vol11.no2.a19400

Abstract

Traffic congestion is a major issue in Surabaya, a metropolitan city with a high rate of private vehicle growth. To address this problem, the Surabaya city government launched the Wira Wiri Suroboyo feeder service as a complement to the Suroboyo Bus mass transportation system. This study aims to identify public responses to the service through sentiment analysis of comments posted on the official Instagram account @wirawirisuroboyo. The methodology employed sentiment analysis and text mining techniques using R Studio software. Data were collected via web scraping from 230 comments and processed through data cleaning, tokenization, case folding, and stopword removal. The results show that 37% of comments were positive, 16% expressed trust, 10% were sad, and 8% were negative. A word cloud revealed dominant words such as "halte" (bus stop), "rute" (route), and "bisa" (can), reflecting the community’s need for better accessibility and service coverage. This research contributes as an evaluation input and recommendation for policymakers to improve the quality and distribution of Wira Wiri Suroboyo services, supporting a more inclusive and sustainable public transport system in Surabaya.
Pirolisis Gelombang Mikro Biomassa Tandan Kosong Kelapa Sawit (TKKS): Pengaruh Massa Absorber KOH dan Katalis Zeolit Alam terhadap Energi Produk Megaprastio, Bayu; Saptoadi, Harwin; Putra, Robertus Dimas Dewangga
Science Tech: Jurnal Ilmu Pengetahuan dan Teknologi Vol 11 No 2 (2025): August
Publisher : Universitas Sarjanawiyata Tamansiswa

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.30738/st.vol11.no2.a19713

Abstract

This study aims to investigate the effect of the KOH/TKKS ratio on the energy content and composition of three-phase pyrolysis products, with a fixed zeolite mass of 10 g. The pyrolysis process was conducted using 100 g of empty fruit bunches (TKKS) at 450 °C with a residence time of 15 minutes. The evaluation covered pyrolysis performance (yields of biochar, bio-oil, and gas), biochar properties (proximate analysis and energy content), bio-oil (energy content), and gas (composition via GC-TCD and energy content). The results show that increasing the KOH ratio accelerated the attainment of the target temperature from approximately 17 minutes (ratio 2:4) to 10 minutes (ratio 4:4) and promoted a higher gas fraction while reducing the bio-oil yield. The optimal condition for bio-oil production was achieved at a KOH/TKKS ratio of 2:4, yielding the highest bio-oil fraction of 29.3%. A higher KOH mass also increased the concentrations of CO, CO₂, and H₂ in the gas phase while decreasing the fixed carbon content in the biochar. The energy input during pyrolysis decreased significantly from 1513.11 kJ at the 2:4 KOH/TKKS ratio to 813.8 kJ at the 4:4 ratio, primarily due to the accelerated heating rate induced by higher KOH content. Despite this, the 2:4 ratio exhibited the highest energy conversion efficiency, as it produced the largest yield and energy content of bio-oil, contributing to a higher total energy output. These findings highlight the critical role of an appropriate KOH ratio in optimizing product distribution and energy efficiency in the pyrolysis process. The results underscore the potential of TKKS as a renewable energy source through microwave-assisted pyrolysis.
Analisis Perbedaan Cadangan Endapan Bijih Nikel Saprolit antara Hasil Eksplorasi dan Realisasi Penambangan pada Blok Penambangan Pulau Gee Triyanto, Bambang; Patimah, Ai Siti
Science Tech: Jurnal Ilmu Pengetahuan dan Teknologi Vol 11 No 2 (2025): August
Publisher : Universitas Sarjanawiyata Tamansiswa

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.30738/st.vol11.no2.a19840

Abstract

This study is part of mining exploration activities, which are crucial to ensure the accuracy of reserve estimates in order to support effective production planning. This is particularly important given the frequent discrepancies between exploration data and actual mining realization. Therefore, a detailed analysis is required to identify the factors causing tonnage deviations in saprolite nickel ore deposits. This study aims to analyze the differences between saprolite nickel ore deposit reserves from exploration results and mining realization at the Gee Island Mining Block and identify the factors influencing these discrepancies. The method used is the area of influence approach, where reserve calculations are based on determining the boundary areas around drill holes, covering half of the area between adjacent drill holes. The mining system applied is an open-pit mine with a mining recovery rate of 90%. The results show that the mined nickel ore tonnage in July was 20,161 tons from exploration, with an actual production tonnage of 19,432 tons, while in August, the exploration tonnage was 25,603 tons, with an actual production tonnage of 24,410 tons. The percentage of tonnage deviation reached 3.62% in July and 4.66% in August. Several factors were identified as causes of tonnage reduction, including drilling spacing and recovery, preparation process, ore extraction technique, and the applied reserve calculation method.
Market Higiene and Sanitation Implementation Study (Case Study: Demangan Market) Sardi, Sardi; Putri, Ceria Nur Utami Novania
Science Tech: Jurnal Ilmu Pengetahuan dan Teknologi Vol 11 No 2 (2025): August
Publisher : Universitas Sarjanawiyata Tamansiswa

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.30738/st.vol11.no2.a20039

Abstract

Demangan Market is one of the public facilities that plays an important role in fulfilling the daily needs of the community. Market activities involve many people, both sellers and buyers, making it a center of social and economic interaction. However, poor market sanitation conditions can increase the risk of contamination exposure and health problems for both visitors and traders. This study aims to analyze the implementation of hygiene and sanitation at Demangan Market, Yogyakarta, based on several assessment parameters and clean water quality indicators. The research employed a quantitative descriptive method by conducting assessments using a market inspection form that includes aspects such as market location, building conditions, sanitation facilities, Clean and Healthy Living Behavior (PHBS), lighting, noise levels, and safety. Water samples were collected from two well points and tested for pH, Total Dissolved Solids (TDS), dissolved oxygen (DO), and iron content (Fe). The research instruments consisted of observation sheets, literature reviews, documentation studies, and laboratory examinations, with data analysis performed using Microsoft Excel. The results indicate that Demangan Market is categorized as less healthy, with an achievement score of 68.22%, which is below the Minimum Main Criteria (≤70%). Meanwhile, the water quality test results show that all samples meet the clean water quality standards based on Ministry of Health Regulation No. 2 of 2023. The six water samples revealed varying results, with pH values ranging from 6.8 to 7.0, TDS values ranging from 151 to 260 mg/L, dissolved oxygen levels ranging from 5.3 to 6.7 mg/L, and iron content (Fe) of 0.00168 mg/L. Based on these findings, it is recommended that the Health Department conduct counseling programs, monitoring, and trader training to improve the implementation of hygiene and sanitation practices, aiming to achieve a Healthy Demangan Market.
Pengaruh Jenis Ban dan Tekanan Angin terhadap Efisiensi Pengereman pada Kendaraan Isuzu TBR 54: Pengaruh Jenis Ban dan Tekanan Angin terhadap Efisiensi Pengereman pada Kendaraan Isuzu TBR 54 Prabandari, Anis; Winarno, Joko; Syamsiro, Mochamad
Science Tech: Jurnal Ilmu Pengetahuan dan Teknologi Vol 11 No 2 (2025): August
Publisher : Universitas Sarjanawiyata Tamansiswa

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.30738/st.vol11.no2.a20165

Abstract

The braking system is a critical component in ensuring the safety of motor vehicles. Braking effectiveness is influenced by the condition of the braking components and supporting factors such as tire type and air pressure. Inappropriate selection of tires or incorrect air pressure can reduce tire grip on the road surface, leading to decreased braking efficiency. Based on this background, this study aims to analyze the effect of variations in tire type (bias and radial) and tire air pressure on the braking efficiency of the Isuzu TBR 54 vehicle. The research was conducted at the Motor Vehicle Testing Unit of the Department of Transportation in Magelang City using an experimental method. A Certus 2023 brake tester was employed to collect data. The variables tested included two types of tires and five different air pressure levels (25, 30, 32, 35, and 40 psi). Braking force data on both vehicle axles were collected and analyzed using SPSS software through normality tests, homogeneity tests, and t-tests to determine the significance of each variable’s influence. The results showed that tire type and air pressure significantly affect braking efficiency. Radial tires demonstrated better braking performance than bias tires across all pressure levels. Excessive air pressure reduced braking efficiency due to a decrease in the tire’s contact area with the road surface. The most optimal combination for braking efficiency is achieved with radial tires at an air pressure of 25–30 psi, which results in braking efficiency above 75%. These findings highlight the importance of selecting the appropriate tire type and maintaining proper air pressure to enhance vehicle safety and braking performance.
Perancangan Sistem Pakar Rekomendasi Jurusan Perguruan Tinggi Universitas PGRI Pontianak Berbasis Web J.H., Baharuddin; Putri, Anggun Cynthia; Hervian, Augenia Angela Angie
Science Tech: Jurnal Ilmu Pengetahuan dan Teknologi Vol 11 No 2 (2025): August
Publisher : Universitas Sarjanawiyata Tamansiswa

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.30738/st.vol11.no2.a20538

Abstract

In Indonesia, the rate of inaccurate major selection among first-year university students reaches 35%, primarily caused by external pressures without adequate self-assessment, leading to a 68% decrease in learning motivation and an increase in the dropout rate by 25%. This study aims to design a web-based expert system using a weighted forward-chaining algorithm to provide accurate major recommendations with a minimum accuracy of ≥80%, while also evaluating user acceptance levels. The research adopts a Research and Development (R&D) approach with a Model-View-Controller (MVC) architecture and a knowledge base comprising 50 decision rules integrating academic performance, RIASEC test results (30 items), non-academic experiences (15 items), and career aspirations (6 items). Validation involved 120 high school students (Grade XII) in West Kalimantan, employing a confusion matrix for accuracy testing and the System Usability Scale (SUS) for usability evaluation. Results show the system achieved 86% accuracy, 85% precision, 87% recall, with an average response time of 2.3 seconds. Expert validation yielded scores ranging from 4.0 to 4.4/5.0, while the SUS score reached 82.5±6.3 (“Excellent” category), with a 40% improvement in user trust through the explanation facility. The proposed expert system effectively provides accurate, adaptive, and user-accepted recommendations, contributing to reducing major mismatch and supporting the digital transformation of higher education.
Rhodamin B Degradation Using Fe-Alginate Gel Beads under UV Light Exposure Andreas, Roy; Setyaningtyas, Tien; Riyani, Kapti
Science Tech: Jurnal Ilmu Pengetahuan dan Teknologi Vol 10 No 1 (2024): Februari
Publisher : Universitas Sarjanawiyata Tamansiswa

Show Abstract | Download Original | Original Source | Check in Google Scholar

Abstract

Heterogeneous Fenton can solve the problem in classic Fenton which is a homogeneous catalyst. Some of the problems with classic Fenton contained sludge production, lost catalysts, and no reuse. This study focuses on the application of Fe-alginate gel beads in the photo-Fenton system using UV light to degrade the dye rhodamine B. After the synthesis step of Fe-alginate gel beads, beads are used to degrade rhodamine B. In addition, the rate of kinetics, mechanism tests, and the reusable tests of Fe-alginate gel beads was also observed. The results confirmed that the degradation value of rhodamine B is 98.8% with the photocatalytic activity is 88.8%. This heterogenous Fenton system fits in first order and •OH is the main radical species to degrade rhodamine B. The reuseable Fe-alginate gel beads were taken out five times, and showed a degradation value of more than 90%. Therefore, it can confirm that the usage of Fe-alginate gel beads as a heterogeneous Fenton may be applied to industrial wastewater processing containing dyes or organic pollutants because this photo-Fenton system is low cost and also be able on visible light.
Pengaruh Phase Change Material Jenis Dry Ice Gel Terhadap Variasi Temperatur pada Dinding Freezer Sena, Boni; Suhendra, Bobie; Amanah, Nadia; Setiawan, Reza; Baihaqi Alfakihuddin, Muhammad Lukman
Science Tech: Jurnal Ilmu Pengetahuan dan Teknologi Vol 10 No 1 (2024): Februari
Publisher : Universitas Sarjanawiyata Tamansiswa

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.30738/st.vol10.no1.a16206

Abstract

The increasing population growth in cities will cause environmental detriments such as global warming and ozone depletion. The electricity need will increase in the future due to the higher temperature in the cities, leading to the higher usage of cooling equipment such as freezers. The current study proposed a method to improve the freezer's energy efficiency by using phase change material of dry ice gel. Most of previous studies only focused on the impact of position of phase change materials on the temperature of wall freezer while no previous studies consider the detailed methodology of measurement and the impact of phase change material based on dry ice gel to the variance of wall temperature. The sensor thermocouple type T and data logger ADAM 6018+ were used to measure the wall temperature of the freezer. The results showed that the sensor thermocouple was verified to the calibrated thermometer with R2 = 0.99. The installation of phase change material based on dry ice gel on the wall freezer could maintain the temperature around 1-2oC while the freezer was turned off for 4, 6, and 8 hours. The efficiency of freezer could be increased from 10% to 30% due to using dry ice gel phase change material. The future study should investigate the various types of phase change materials and the new combination of phase change materials.

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